Obstetric admissions to intensive care units in Australia and New Zealand: a registry‐based cohort study

Abstract

Objective Describe the epidemiology of obstetric patients admitted to an Intensive Care Unit (ICU). Design Registry‐based cohort study. Setting 183 ICU’s in Australia and New Zealand. Population Women aged 15 to 49 years, admitted to ICU between 2008 and 2017, classified as pregnant, post‐partum, or with an obstetric‐related diagnosis. Methods Data was extracted from the Australia and New Zealand Intensive Care Society (ANZICS) Adult Patient Database, and national agencies. Main outcome measures Incidence of ICU admission, cohort characteristics, maternal outcomes and changes over time. Results The cohort comprised 16,063 patients. The annual number of obstetric ICU admissions increased, while their proportion of total ICU admissions (1.3%) did not change (Odds Ratio 1.02; 95% CI, 0.99 – 1.04, P=0.14). There were 10,518 (65%) with an obstetric‐related ICU diagnosis, and 5,545 (35%) with a non‐obstetric ICU diagnosis. Mean (SD) age was 31 (6.4) years, 1,463 (9.1%) were Indigenous, 2,305 (14%) were transferred from another hospital, and 3,008 (19%) received mechanical ventilation. Median [IQR] length of stay in hospital was 5.2 [3.1 – 7.9] days, which included 1.1 [0.7 – 1.8] days in ICU. There were 108 (0.7%) maternal deaths, most (N=97, 90%) having a non‐obstetric diagnosis. There was no change in risk‐adjusted length of stay or mortality over time. Conclusions Obstetric patients account for a stable proportion of ICU admissions in Australia and New Zealand. These patients typically have a short length of ICU stay and low hospital mortality.